Download or read book Erosion and Rolling Contact Wear Mechanisms in Silicon Nitride Hybrid Bearings written by Balamurugan Karunamurthy and published by . This book was released on 2009 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Wear Mechanisms of Silicon Nitride Bearing Materials Under Contact Fatigue Stresses written by Zheng Chen and published by . This book was released on 1995 with total page 428 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ceramic Bearing Development Vol 1 Fatigue and Wear Behavior of NBD 200 Silicon Nitride Balls written by and published by . This book was released on 1995 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt: These are the test results of the fatigue and wear performance of NBD-200, silicon nitride balls under conditions of rolling contact in ball bearings. Life testing was done under conditions of load and EHD film thickness equal to or more severe than those to be expected in turbine engine mainshaft applications. The actual temperatures and speeds of those applications were not simulated. No fatigue failures occurred in a sample of 556 'standard' NBD-200 balls within a test limit of five times the experimentally - determined L-10 life of the AISI 52100 steel balls. Ball failures did occur in a sample of balls identified by a Surface Acoustic Wave NDE technique as being flawed, but the correspondence between the estimated severity of the flaws and the specific ball failures was not good. A Thermal Proof Testing technique for eliminating balls with flaws may possibly have promoted failures of balls that otherwise would have performed satisfactorily. Wear tests, performed under moderate to severe boundary lubrication conditions showed no measurable, 'conventional' wear. The life - limiting factor in these hybrid bearings was microspalling of the AISI 52100 and M-50 steel races.
Download or read book Effect of Silicon Nitride Balls and Rollers on Rolling Bearing Life written by Erwin V. Zaretsky and published by BiblioGov. This book was released on 2013-06 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: Three decades have passed since the introduction of silicon nitride rollers and balls into conventional rolling-element bearings. For a given applied load, the contact (Hertz) stress in a hybrid bearing will be higher than an all-steel rolling-element bearing. The silicon nitride rolling-element life as well as the lives of the steel races were used to determine the resultant bearing life of both hybrid and all-steel bearings. Life factors were determined and reported for hybrid bearings. Under nominal operating speeds, the resultant calculated lives of the deep-groove, angular-contact, and cylindrical roller hybrid bearings with races made of post-1960 bearing steel increased by factors of 3.7, 3.2, and 5.5, respectively, from those calculated using the Lundberg-Palmgren equations. An all-steel bearing under the same load will have a longer life than the equivalent hybrid bearing under the same conditions. Under these conditions, hybrid bearings are predicted to have a lower fatigue life than all-steel bearings by 58 percent for deep-groove bearings, 41 percent for angular-contact bearings, and 28 percent for cylindrical roller bearings.
Download or read book Effect of Silicon Nitride Balls and Rollers on Rolling Bearing Life written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-05-30 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: Three decades have passed since the introduction of silicon nitride rollers and balls into conventional rolling-element bearings. For a given applied load, the contact (Hertz) stress in a hybrid bearing will be higher than an all-steel rolling-element bearing. The silicon nitride rolling-element life as well as the lives of the steel races were used to determine the resultant bearing life of both hybrid and all-steel bearings. Life factors were determined and reported for hybrid bearings. Under nominal operating speeds, the resultant calculated lives of the deep-groove, angular-contact, and cylindrical roller hybrid bearings with races made of post-1960 bearing steel increased by factors of 3.7, 3.2, and 5.5, respectively, from those calculated using the Lundberg-Palmgren equations. An all-steel bearing under the same load will have a longer life than the equivalent hybrid bearing under the same conditions. Under these conditions, hybrid bearings are predicted to have a lower fatigue life than all-steel bearings by 58 percent for deep-groove bearings, 41 percent for angular-contact bearings, and 28 percent for cylindrical roller bearings.Zaretsky, Erwin V. and Vlcek, Brian L. and Hendricks, Robert C.Glenn Research CenterFATIGUE LIFE; ROLLER BEARINGS; ROLLERS; SILICON NITRIDES; SERVICE LIFE; PREDICTIONS; STRESSES
Download or read book Rolling Wear of Silicon Nitride Bearing Materials written by John W. Lucek and published by . This book was released on 1990 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Rolling-contact fatigue test methods were used to measure the wear performance of several silicon nitride materials. Sintered, hot pressed and hot isostatically pressed materials exhibited wear rates ranging over three orders of magnitude. Hot isostatically pressed materials had the lowest wear rates. Despite the disparity in wear performance, all materials tested had useful rolling-contact fatigue lives compared to steel. Fatigue life estimates, failure modes, and rolling wear performance for theses ceramics are compared to M-50 steel. This work highlights the rapid contact stress reductions that occur due to conformal wear in rolling-contact fatigue testing. Candidate bearing materials with unacceptably high wear rates may exhibit useful fatigue lives. Rolling contact bearing materials must possess useful wear and fatigue resistance. Proper performance screening of candidate bearing materials must describe the failure mode, wear rate, and the fatigue life. Guidelines for fatigue testing methods are proposed.
Download or read book Ceramic Materials in Rolling Contact Bearings written by William M. Wheildon and published by . This book was released on 1973 with total page 93 pages. Available in PDF, EPUB and Kindle. Book excerpt: The contract for investigation of ceramic materials in rolling contact bearings, was carried out with high strength silicon nitride, silicon carbide and aluminum oxide. Screening rolling contact fatigue testing on silicon nitride with conventional lubricants showed excellent life, greater than M50 steel, at comparable load. The friction and wear properties were determined for silicon nitride, silicon carbide and steel. The coefficient of friction and wear rates are nearly the same for steel-steel and steel-silicon nitride combinations.
Download or read book Wear of Materials written by Peter J. Blau and published by Elsevier. This book was released on 2003-10 with total page 1540 pages. Available in PDF, EPUB and Kindle. Book excerpt: The 14th International Conference on Wear of Materials took place in Washington, DC, USA, 30 March - 3 April 2003. These proceedings contain over two-hundred peer reviewed papers containing the best research, technical developments and engineering case studies from around the world. Biomaterials and nano-tribology receive special attention in this collection reflecting the general trends in the field. Further highlights include a focus on the new generation of instrumentation to probe wear at increasingly small scales. Approximately ninety communications and case studies, a popular format for the academic community have also been included, enabling the inclusion of the most up-to-date research. Over 200 peer-reviewed papers including hot topics such as biomaterials and nano-tribology Keeping you up-to-date with the latest research from leading experts Includes communications and case studies
Download or read book Performance Improvement of Silicon Nitride Ball Bearings by Ion Implantation CRADA Final Report written by and published by . This book was released on 1998 with total page 43 pages. Available in PDF, EPUB and Kindle. Book excerpt: The present report summarizes technical results of CRADA No. ORNL 92-128 with the Pratt and Whitney Division of United Technologies Corporation. The stated purpose of the program was to assess the 3effect of ion implantation on the rolling contact performance of engineering silicon nitride bearings, to determine by post-test analyses of the bearings the reasons for improved or reduced performance and the mechanisms of failure, if applicable, and to relate the overall results to basic property changes including but not limited to swelling, hardness, modulus, micromechanical properties, and surface morphology. Forty-two control samples were tested to an intended runout period of 60 h. It was possible to supply only six balls for ion implantation, but an extended test period goal of 150 h was used. The balls were implanted with C-ions at 150 keV to a fluence of 1.1 x 1017/cm2. The collection of samples had pre-existing defects called C-cracks in the surfaces. As a result, seven of the control samples had severe spalls before reaching the goal of 60 h for an unacceptable failure rate of 0.003/sample-h. None of the ion-implanted samples experienced engineering failure in 150 h of testing. Analytical techniques have been used to characterize ion implantation results, to characterize wear tracks, and to characterize microstructure and impurity content. In possible relation to C-cracks. It is encouraging that ion implantation can mitigate the C-crack failure mode. However, the practical implications are compromised by the fact that bearings with C-cracks would, in no case, be acceptable in engineering practice, as this type of defect was not anticipated when the program was designed. The most important reason for the use of ceramic bearings is energy efficiency.
Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1987 with total page 338 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Experimental and Computed Performance Characteristics of High Speed Silicon Nitride Hybrid Ball Bearings written by George W. Hosang and published by . This book was released on 1990 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Development testing of hybrid bearings with M.50 rings and HIPed silicon nitride balls in small high-speed turbojet engines was carried out for several minutes at speeds up to 110,000 rpm. The main rotor system comprised an overhung radial compressor and turbine monorotor assembly with a pair of preloaded 101-size bearings. Estimated aerodynamic thrust of up to 750 N (170 lb) was added to the 200 N (45 lb) preload on the bearing adjacent to the compressor. Some testing was carried out with MIL-L-7808 air/oil mist and some with JP-10 fuel supplied in a similar fashion. After each test phase the bearings were removed for examination and re-used or replaced. Four of the bearings were submitted to inspection with special equipment to measure operating contact angles, as evidenced by the visible ball tracks, and any wear present. Contact angles and other operating characteristics estimated with the Jones, "SHABERTH," and "ADORE" computer codes were compared with the experimental data.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 892 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Surface Endurance and Lubrication of Silicon Nitride Ball Bearings written by H. Dalal and published by . This book was released on 1975 with total page 81 pages. Available in PDF, EPUB and Kindle. Book excerpt: A report is made on the effect of using silicon nitride balls on the rolling contact fatigue life of radially loaded M50 steel ball bearings. Scanning electron microscope (SEM) examination of the surface topography of as-manufactured silicon nitride ball surfaces is described and compared with silicon nitride ball and flat washer surfaces tested previously. The rolling-contact fatigue performance of previously tested all-tool-steel bearings is compared with the present group of bearings containing silicon nitride balls as well as with previously tested silicon nitride flat washers run against tool steel rollers. It is shown that the life of the present group of bearings is controlled by the life of the currently available silicon nitride ball complement. This is contrary to the previous flat washer life results. The ball groove surfaces of the present steel bearing rings after running against the silicon nitride balls is described.
Download or read book Friction and Wear written by Giovanni Straffelini and published by Springer. This book was released on 2015-04-03 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book introduces the basic concepts of contact mechanics, friction, lubrication, and wear mechanisms, providing simplified analytical relationships that are useful for quantitative assessments. Subsequently, an overview on the main wear processes is provided, and guidelines on the most suitable design solutions for each specific application are outlined. The final part of the text is devoted to a description of the main materials and surface treatments specifically developed for tribological applications and to the presentation of tribological systems of particular engineering relevance. The text is up to date with the latest developments in the field of tribology and provides a theoretical framework to explain friction and wear problems, together with practical tools for their resolution. The text is intended for students on Engineering courses (both bachelor and master degrees) who must develop a sound understanding of friction, wear, lubrication, and surface engineering, and for technicians or professionals who need to solve tribological problems in their work.
Download or read book Wear Mechanisms of High Speed Roller Bearings and Finite Element Analysis of Contact Stress and Crack Propagation written by Nelca Tunca and published by . This book was released on 1985 with total page 462 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Investigation of Wear Mechanisms in Rolling Contact written by Michel Pons and published by . This book was released on 1981 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Handbook of Materials Selection for Engineering Applications written by George Murray and published by CRC Press. This book was released on 1997-07-03 with total page 633 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reflecting the rapid advances in new materials development, this work offers up-to-date information on the properties and applications of various classes of metals, polymers, ceramics and composites. It aims to simplify the materials selection process and show how to lower materials and manufacturing costs, drawing on such sources as vendor supplie
